Leksell's unpublished pallidotomies of 1958-1962

Lars Leksell performed posteroventral pallidotomies in 123 parkinsonian patients from 1958 through 1962. This previously unpublished series was analyzed by the present author 40 years later. The analysis was based on a number of old radiographs that were found accidentally as well as the available hospital notes. After pallidotomy, Leksell had left metal markers in the brain to illustrate the lesion site. Superimposition of the markers on modern MRI scans of patients with similar-sized heads shows a high degree of accuracy of Leksell's pallidotomy.